The biggest winner in the stop-and-frisk lawsuit against the city is the court-appointed federal monitor in charge of NYPD oversight.

White-shoe lawyer Peter Zimroth’s fees, which come to $43,750 a month — $525,000 annually — will be picked up by the taxpayers.

Under an agreement with the de Blasio administration filed Friday, Zimroth — who was corporation counsel under then-Mayor Ed Koch — is being paid for work he has done since November.

He defended the big payday, telling The Post he’s being compensated by the city at a “less substantial rate” than what his firm charges private- practice clients.

He added he might wind up splitting part of his fee with office colleagues who assist him.

Zimroth also said the all-inclusive fee is a lot less than he would have gotten had he billed by the hour.

The three-year deal, a city Law Department spokesman said, will “save taxpayers’ money . . . The hourly fees for this same work would have been much, much higher.’’

Zimroth was appointed monitor in August 2013 as part of a controversial ruling by Judge Shira Scheindlin that found the NYPD’s stop-and-frisk practices unconstitutional because, she said, they unfairly targeted minorities.

The monitor is charged with making sure her orders are carried out.

Zimroth also pointed out that he is not billing the city for any work he performed over the first 15 months.

During that period, police unions were appealing the judge’s ruling.

Also being well-paid through the stop-and-frisk settlement is Ariel Belen.

He stepped down three years ago as a Brooklyn Supreme Court judge to join the private sector because he was unhappy with judicial pay.

As the court-appointed “facilitator” earning $600 an hour, he is supposed to assist Zimroth by hosting town-hall-type meetings and working with plaintiffs, community leaders and city officials to develop reforms.

Belen will have three underlings earning between $75 and $300 an hour.

Zimroth will have seven consultants at his disposal earning between $200 and $350 an hour.

They include a lawyer, law professors and a former cop from Lowell, Mass.

Zimroth is a partner at the international law firm of ­Arnold & Porter.

The former Manhattan federal prosecutor is married to Oscar-winning actress Estelle Parsons.

Zimroth’s fees are actually a bargain when compared to those of attorney Mark Cohen, the court-appointed monitor who oversees the FDNY’s controversial minority-hiring program.

The Post reported in December 2013 that he burned through more than $3 million in taxpayer funds through his first two years of a 10-year consulting gig.